scholarly journals Peculiarities of Aluminum Anodization in AHAs-Based Electrolytes: Case Study of the Anodization in Glycolic Acid Solution

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5362
Author(s):  
Lidia Zajączkowska ◽  
Małgorzata Norek

The anodization of aluminum (Al) in three alpha-hydroxy acids (AHAs): glycolic (GC), malic (MC), and citric (CC), was analyzed. Highly ordered pores in GC were obtained for the first time. However, the hexagonal cells were characterized by a non-uniform size distribution. Although common features of current density behavior are visible, the anodization in AHAs demonstrates some peculiarities. The electric conductivity (σ) of 0.5 M GC, MC, and CC electrolytes was in the following order: σ(CC) > σ(MC) > σ(GC), in accordance with the acid strength pKa(CC) < pKa(MC) < pKa(GC). However, the anodization voltage, under which a self-organized pore formation in anodic alumina (AAO) was observed (Umax), decreased with increasing pKa: Umax(CC) > Umax(MC) ≥ Umax(GC). This unusual behavior is most probably linked with the facility of acid ions to complex Al and the active participation of the Al complexes in the AAO formation. Depending on the AHA, its tendency and different modes to coordinate Al ions, the contribution of stable Al complexes to the AAO growth is different. It can be concluded that the structure of Al complexes, their molecular mass, and the ability to lose electrons play more important roles in the AAO formation than pKa values of AHAs.

1996 ◽  
Vol 422 ◽  
Author(s):  
M. R. Bennett ◽  
K. E. Singer ◽  
A. C. Wright ◽  
Z. H. Jafri

AbstractThe growth of epitaxial GaAs doped with the rare earth thulium (Tm) by MBE is reported for the first time. The nature of the incorporation of Tm has been studied using SIMS, RBS, TEM, PL and DCXRD. Sharp doping profiles have been observed by SIMS from samples doped in a staircase structure. Under standard GaAs growth conditions, TEM has revealed a solubility limit of ∼5×1019cm−3, above which Tm precipitates as spherical nano-particles of uniform size (1.3–1.7nm). High resolution TEM has provided no evidence for strain relaxation around these precipitates. Growth at higher substrate temperatures (≥620°C) or at As:Ga ratios close to stoichiometry, results in the formation of precipitate wires and/or bifurcated structures (“quantum trees”) aligned approximately in the direction of growth. Such behaviour is in common with that of Er in GaAs and suggests that the precipitates result from the self-organised growth of TmAs. Mechanisms for the formation of the quantum wires and trees are suggested. Initial photoluminescence spectra from these samples show two groups of narrow Tm3+ intra 4f transition lines corresponding to the 3H5 – 3H6 (∼1.01eV/1.2μm) and 3H4 – 3H6 (∼ 0.71eV/1.7μm) transitions. The spectra exhibit an excellent correlation with those obtained from samples grown by MOVPE and also those implanted with Tm by other groups.


2017 ◽  
Vol 11 (1) ◽  
pp. 35-63
Author(s):  
Ruth Roded

Beginning in the early 1970s, Jewish and Muslim feminists, tackled “oral law”—Mishna and Talmud, in Judaism, and the parallel Hadith and Fiqh in Islam, and several analogous methodologies were devised. A parallel case study of maintenance and rebellion of wives —mezonoteha, moredet al ba?ala; nafaqa al-mar?a and nush?z—in classical Jewish and Islamic oral law demonstrates similarities in content and discourse. Differences between the two, however, were found in the application of oral law to daily life, as reflected in “responsa”—piskei halacha and fatwas. In modern times, as the state became more involved in regulating maintenance and disobedience, and Jewish law was backed for the first time in history by a state, state policy and implementation were influenced by the political system and socioeconomic circumstances of the country. Despite their similar origin in oral law, maintenance and rebellion have divergent relevance to modern Jews and Muslims.


Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 237
Author(s):  
Jennifer Gravrok ◽  
Dan Bendrups ◽  
Tiffani Howell ◽  
Pauleen Bennett
Keyword(s):  

The authors wish to make the following corrections [1]:In Table 1, under case study 4, the code was originally labeled as H8, P8 and ADI 8; these labels should be H4, P4 and ADI 4, respectively [...]


Author(s):  
Halil Kayaduman ◽  
Turgay Demirel

The purpose of the study is to investigate the concern developments of first-time distance education instructors using the concerns-based adoption model (CBAM). This study used stages of concern (SoC), a component of CBAM, as its theoretical framework. A descriptive case study was implemented, which focused on the adaptation processes of nine instructors lecturing for the first time via distance education. The instructors attended a two-day training, which was designed based on their initial concerns. Then instructors implemented their courses for four weeks via distance education. While the informational and personal stages (self-concerns) decreased compared to the initial findings, the consequence stage increased in intensity. However, self-concerns remained predominant in the process despite the reduction in self-concerns and increase in the consequence stage. Based on the findings, the implications for distance education and recommendations for addressing the instructors’ concerns are discussed. Recommendations for alleviating the concerns of first-time distance education instructors include: the provision of ongoing concern-based interventions that incorporate technological, pedagogical, and content knowledge; providing working examples related to distance education from which instructors can learn vicariously; and encouraging collaboration among instructors.


2021 ◽  
Vol 11 (14) ◽  
pp. 6452
Author(s):  
César Ricardo Soto-Ocampo ◽  
Juan David Cano-Moreno ◽  
José Manuel Mera ◽  
Joaquín Maroto

Increasing industrial competitiveness has led to an increased global interest in condition monitoring. In this sector, rotating machinery plays an important role, where the bearing is one of the most critical components. Many vibration-based signal treatments are already being used to identify features associated with bearing faults. The information embedded in such features are employed in the construction of health indicators, which allow for evaluation of the current operating status of the machine. In this work, the use of contour maps to represent the diagnosis map of a bearing, used as a health map, is presented for the first time. The results show that the proposed method is promising, allowing for the satisfactory detection and evaluation of the severity of bearing damage. In this initial stage of the research, our results suggest that this method can improve the classification of bearing faults and, therefore, optimise maintenance processes.


2010 ◽  
Vol 67 (8) ◽  
pp. 1291-1302 ◽  
Author(s):  
Helder Cunha Pereira ◽  
Norman Allott ◽  
Catherine Coxon

This paper compares, for the first time, nutrient levels and chlorophyll a measured in a set of seasonal lakes with those reported for permanent lakes in the literature. Twenty-two turloughs (karstic seasonal lakes) in western Ireland were sampled monthly from the onset of flooding (October) until they dried out (6 to 9 months). The turloughs showed similar levels of nutrients and chlorophyll a to those reported for Irish and international lakes. Chlorophyll a peaked between November and February in the majority of turloughs, sometimes with values higher than those measured in mesotrophic lakes in summer. A significant log-linear regression was found between total phosphorus and chlorophyll a, which suggests P limitation of algal biomass in the majority of the turloughs. The regression characteristics were not significantly different than those described in similar studies of permanent lakes. Patterns in seasonal variation of nutrients are also presented, their underlying causes being discussed in relation to their transport within catchments. Our results show that despite being predominantly winter phenomena, turloughs can be as productive as permanent lakes.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Muhammad Iqbal Baiquni

<div><p class="abstract">The case of espionage or spying by Australia against Indonesia is not the first time, but there have been several attempts of espionage against Indonesia. This espionage act is an act of secretly collecting intelligence data in international relations in a country. In this paper, we discuss the wiretapping case and its resolution. This paper uses normative legal research with a qualitative approach. This paper examines the chronology of cases of tapping by Australia against Indonesia, wiretapping in human rights and international law, as well as the final settlement of tensions between Indonesia and Australia through an agreement on the Code of Conduct to normalize bilateral relations between the two countries.</p></div>


2021 ◽  
Vol 37 (2) ◽  
Author(s):  
Przemysław Filipiak ◽  
Anna Jaskóła ◽  
Karolina Gattner

Objectives. Psoriasis makes a relative contraindication for lithium treatment which can exacerbate its symptoms or induce it itself. On the other hand, lithium exerts immuno-modulatory activity. Case study. In this paper, a case of a female patient is presented. The patient has been treated since 2012 for bipolar affective illness (bipolar disorder – BD) and psori­asis, which occurred for the first time during a depress­ive episode. Despite intensive pharmacological treatment, both as inpatient and outpatient, a satisfactory improvement of affective illness has not been obtained. After the introduction of lithium, a remission of BD was achieved as well as a reduction of psoriatic changes, which have been maintained until now (2021). Conclusion. The remission of Bipolar Disorder (BD) on lithium can suggest that the patient belongs to the group of the so-called excellent lithium responders. In the presen­ted case remission of psoriasis was observed during lithium treatment. This case report must be treated with caution because remission could be spontaneous and the patient needs further observation.


2016 ◽  
Vol 12 (7) ◽  
pp. 159
Author(s):  
Seyed Mehdi Khadem ◽  
Darush Rahmati ◽  
Ali Yavari ◽  
Seyed Ehsan Etemadifar ◽  
Alireza Eftekharian

The goal of this research is to prioritize effective factors on motivating employees to keep on working and determining the most important effective factors on the employees' motivation. In this paper, to grade effective factors on the employees' motivation for keeping on to work, the Fuzzy AHP method, which is one of the multi-standard decision-making methods was utilized. Field research and library research methods were used for collecting the needed information.  Results indicated that among the effective factors on the employees' motivation for job persistence, the health factor is the most important and financial status is the second most important factor. The least importance is given to the significance of the work for that person. In this paper, the effective factors on the employees' motivation for job persistence were rated for the first time. Results of this research are very useful in devising strategies that are related to keeping employees for the human resources' executives. The results of this paper are not applicable to all organizations. Furthermore, in this research, only the factors with positive impacts on employees for job persistence were rated.


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